The selection of a certain actuator type depends on the application requirements and restrictions and on cost constraints of the system. The type of actuators compared are hydraulic, pneaumatic and electrical.
In this qualitative comparison not the maximum achievable performances, but rather the standard widely available ones are compared.
The hydraulic actuators are best suited for high forces and torques, followed by the electric actuators.
An important characteristic property of an actuator is the force density (force/volume or force/weight). The highest force density is inherent in the hydraulic actuators. However, if the volume(weight) of the motor, the pump and other necessary components are taken into consideration, electric actuators offer almost the same or even higher force density. In applications where number of actuators are required, hydraulic system with a central pump station is frequently more economical solution. Electric actuators have the highest energy efficiency. Hydraulic and pneumatic systems frequently need continuously running pumps or compressors, even though the actuator is not performing any motion.
Due to the compressibility of the gas or fluid and because of the less exact control characteristics of the hydraulic and pneumatic valves, the positioning accuracy of the hydraulic and pneumatic actuators is lower than the electric systems. Some servo hydraulic or servo pneumatic systems can reach a fairly high positioning accuracy and good repeatability but cannot reach the performance of pure electric or electromechanical systems. The costs of servo hydraulic system are usually considerably higher than the costs for a same performance electric actuator. There is practically no environmental hazard associated with electric actuators; on the other hand, the hydraulic systems constitute a constant danger due to the possible leakage of hydraulic fluid. The electric actuators feature the most balanced overall performance.The increased performance,reliability and affordability of state of theart motors and electronic motion controls gives a strong boost for the electricactuators. In countless automation applicatlons, where about a decade agoonly hydraulic or pneumatic actuatorswere used, electric actuators are takingover the field.There are still a number of high forcedensity requiring applications wherethe hydraulic actuator is a better choice.The developments in the servo hydraulic and servo pneumatic field helped toimprove the positioning accuracy andcontrol capability of these types of actuators.Despite this, the utilization ofelectric actuators is growing more rapidly and this tendency will most likely continue or even accelerate.
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FAQs
Affected parameters for actuator selection include the availability of a power source, torque and size of the valve, failure mode, speed of operation, frequency and ease of operation, control accessories, hazardous area, and cost.
What are the different types of actuators and how do they work? ›
Actuators are largely classified by the type of motion they create and what type of power source they operate on. In terms of the latter, actuators create either linear or rotary motion. Linear actuators create motion in a straight line, while rotary actuators create motion in a circular or rotational fashion.
What are the factors affecting the selection of actuators? ›
Factors Affecting The Choice of Actuators
To choose the most effective actuator for a particular application, critical information must first be ascertained. Factors such as load capacity, operation speed, stroke length, environment, orientation, and positional accuracy have to be identified and quantified.
How to choose a proper actuator that is suitable for a specific application? ›
Steps for choosing the right actuator for your application
- Understanding the kind of movement that is required in the application. ...
- Assess the level of precision that you need from the actuator. ...
- Take into consideration the energy input. ...
- Access the amount of force you require. ...
- Ascertaining the speed of the actuator.
Actuators can be categorized based on their movement type, either linear or rotary. Linear actuators produce linear motion in a straight line, while rotary actuators produce rotary motion in a circular path.
What are the requirements for an actuator? ›
An actuator requires a control device (controlled by control signal) and a source of energy. The control signal is relatively low energy and may be electric voltage or current, pneumatic, or hydraulic fluid pressure, or even human power.
What are the most commonly used actuators? ›
Here are some of the most common types:
- Rotary Valve Actuator. This is a type of valve actuator that takes various kinds of power, such as electricity and pneumatics, in order to turn it into mechanical energy. ...
- Linear Valve Actuator. ...
- Lead Screw Actuator. ...
- Pneumatic Actuator. ...
- Manual Valve Actuator.
The main types of robotic actuators are electric, hydraulic, and pneumatic actuators. Each type has its unique characteristics and applications, depending on factors such as required force, speed, precision, and operating environment.
What are the four actuators? ›
There are four basic types of linear actuators: mechanical/electro mechanical, hydraulic, pneumatic and piezoelectric.
What are the key characteristics of actuators? ›
The three major characteristics of actuators are accuracy, precision, and reliability. The definitions of these parameters is consistent with the corresponding definitions given earlier for sensors. The most fundamental control of any equipment is the ability to turn it on/off.
Sensor selection criteria include temperature, size, protection class, and whether the sensor requires a discrete or analog input. Also consider sensor repetition accuracy, sensor response speed, and sensing range.
What primary factors should be considered in the selection of control valves? ›
Process conditions: Consider the temperature, pressure, and fluid characteristics of your application. Some control valves may be better suited for high-pressure environments, while others may have specific material requirements for certain types of fluids.
What are the criteria for actuator selection? ›
Actuator Selection Criteria
Force or torque requirements: Force or torque requirements are among the most critical factors to consider when selecting an actuator. The actuator must be capable of generating sufficient force or torque to move the load in the desired manner.
What is the most efficient type of actuator? ›
Electric actuators have the highest energy efficiency. Hydraulic and pneumatic systems frequently need continuously running pumps or compressors, even though the actuator is not performing any motion.
What are the most precise actuators? ›
High precision linear actuator methods include:
- Friction screws with anti-backlash nuts.
- Ball screws.
- Belt and pulley.
- Rack and pinion.
- Piezo actuators.
- Linear motors.
When selecting a control valve for process plant, there are many things to be considered. These can include the valve flow characteristic, size, valve body and trim materials, noise, potential for damage from cavitation or flashing, actuator type and size, dynamic response to changes in control signal etc.
